Telephone-exchange system.



H. P. CLAUSEN.

TELEPHONE EXCHANGE SYSTEM.

APPUCATION FlLED NOV. 6.1915- Patented June 19, 1917.

TB SATES PAT FFIQE.

HENRY P. CLAUSEN, OF MOUNT VERNON, NEW YORK, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Be it known that I, HENRY P. GLAUsnN, a citizen of the United States, residing at Mount Vernon, in the county of Testchester and State of New York, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a full, clear, concise description.

This invention relates to improvements in telephone exchange systems, and has for its principal object to provide means for facilitating the handling of connections at a telephone switchboard.

The invention in its broader aspects consists in the provision of means whereby an operator at a switchboard position may, while completing a connection between two subscribers lines with one link circuit, connect the answering end of a second link circuit with the line of another calling subscriber, and have the telephone set immediately connected with such second link circuit the instant that the connection involving the first link circuit is completed.

In accordance with this invention, link circuits equipped with relays for auto1natically connecting an operators telephone set with the talking strands of the link circuits, are provided with switching means common to the link circuits and adapted to permit the answering end of more than one of the link circuits to be joined for answering respective subscribers lines at the same time. The common switching means acts as a guard to prevent the inclusion of the operators telephone set with more than one of such connected link circuits at the same time, and operates automatically upon the completion of the connection to automatically connect the operators telephone with the next link circuit which is taken for a connection.

Means including relays and a circuit interrupter means are also provided for automatically flashing a pilot signal and the supervisory signal of a link circuit 'con nected for answering a subscribers line dur ing the period the operators telephone set is connected with the first one of the link circuits. T he apparatus controlling the flashing of the answering supervisory signal is Specification of Letters Patent.

Patented June 19, 1917.

Application filed November 6, 1915. Serial No. 59,972.

also arranged so that, should the calling subscriber wish to attract the attention of the operator, the subscriber may, byrestoring and then removing the receiver from the switchhook, cause the automatic flashing.

This invention is illustrateddiagrammatically in the accompanying drawing, in which a completely equipped subscribers line circuit of a welLknown central-energy type is shown at 1; and two switchboard jacks, which may be considered as connected to other subscribers lines'having equipment identical withthat shown at 1, are respectively indicated by the numerals 2 and 3. At 4 is shown a completely equipped link circuit, and at 5, 6 and 7 are indicated, respectively, such portions of three additional link circuits as will be necessary in describing the relation of the common relay to a plurality of link circuits.

Briefly described, the operating features of this system are as follows: When the answering end'of a link circuit is connected to a subscribers linein' answering a call, a relay includes an associated operators telephone set with the link circuit; a common relay disables the listening relays of other link circuits, and a flashing control relay on this link circuit is disabled. If now, another link circuit is connected to a second 's'uloscribers line in preparing to answer another call, its listeningrelay will remain inert, and its flashing-control relay will cause a pilot lamp common to the position and the supervisory lamp of this link circuit to be automatically flashed. On connecting the calling half of the first link circuit with another subscribers line, as in completing a connection, the listening relay disconnects the operators telephone set from this link circuit, disconnects the common relay, and the flashing-control relay prepares a circuit to render a flashing recall signal on the supervisory lamp of this link circuit and the pilot lamp, in case the subscriber first answered attempts to again call the operator before the connection has been taken down.

"of this link circuit.

common relay re-operates, and theflashing control relay discontinues the flashing operations of the pilot lamp and supervisory lamp Other operations necessary in completing the second connection set up circuit actions which correspond with those already described in handling the first connection.

In more specifically describing the operation of this system in connection with the drawing, insertion of a plug 11 in a jack 12 includes the main or talking conductors of the link circuit 4 with the subscribers line 1, and completes another circuit through a battery 10, the contacts 16 of a relay 15, contacts 18 of a common relay 17, conductor 19, the winding of a listening-relay 22, conductor 32, the signal-circuit contacts of the plug 11 and the jack 12, the winding of a cutolf relay 13, to earth. The relay 13 disconnects its associated line relay from the line circuit 1. The several circuit changes set up by the operation of the listening relay 22 are: first, at its contacts 26 to disable the circuit of a flashing-control relay 35; second, through its contacts 23 and 24 to include an operators telephone set 33 with the link circuit 4; third, through its contacts 27 and a conductor 20 to complete a path from the con tacts 16 of the relay 15 independently of the contacts 18 of the common relay 17; and fourth, through its contacts 25 to connect the battery 10 over conductor 30, the Winding of the common relay 17, to earth. Although the operation of the common relay 1'7 and the separation of its several contacts 18 disable the listening relays 22 associated with the link circuits 5, 6 and 7, the listening relay at the link circuit 4 is retained through its locking contacts 27, as traced. Talking current from the battery 10 is supplied to the subscribers instrument on the line circuit 1 over the right and left hand windings of a supervisory relay 40. Assuming that this subscribers instrument is now in the talking position, this relay will be energized in the well-known way. Circuits for controlling the operation of a supervisory lamp 44 may now be traced through the battery 10, the contacts 39 of the relc y 35, contacts 41 of the relay 40, and a resistance 45 to a junction with the conductor 32, thereby forming a parallel path with the circuit through the winding of the listening relay 22, and completing circuit at the earth connection of the cut-off relay 13 as traced. Al-

. though the supervisory lamp 44 is connected through the battery 10 to the resistance unit 45, it is at this time extinguished, due to the shunt path as traced through the contacts 41 of the supervisory relay 40.

Assumingv that 'the subscriber 1, now in communication with an operator 33, requests tobe connected with a subscriber whose line to earth. A supervisory lamp 55 connected from the battery 10 through the contacts 58 of a supervisory relay 57 is now lighted through this circuit Which is in parallel with the winding of the relay 15. Separation of the contacts 16 of the relay 15 releases the listening relay 22, which in turn disconnects the operators telephone set 33 from the link circuit 4 and releases the common relay 17. The closing of the contacts 26 of the relay 22 prepares a circuit for the subsequent operation of the relay 35, as will presently be described. In order to ring the bell of the subscriber 2, the operator now momentarily depresses a key 64, thereby completing a circuit through the battery 10, the contacts 43 of the relay 40, conductor 61, the winding of a ringing control relay 62, conductor 63, and the key 64 to earth. A circuit through the contacts 65 of the relay 62 and contacts 71 of a relay 70 to earth, is now substituted for the circuit through the key 64 to retain the relay 62, after the key 64 has been released. The contact members 66 and 67 of the relay 62 disconnect the calling plug 14 from the link circuit 4 and connect a source of grounded ringing current (not shown), indicated as feeding through the Winding of a trip relay 70, to the subscrib ers line 2. 7

When the subscriber 2 responds to this call by removing the receiver from its switch-v hook, the relatively low resistance of the talking circuits of the instrument permits a sufficient increase in the amount of ringing current through the winding of the trip relay 70 to cause it to operate, and at its contacts 71 to open the circuit of-the ringing control relay 62. The release of the relay 62 causes its contact members 66 and 67 v to disconnect the source of ringing current from the 'line 2 and reconnect the callingplug 14 with the link circuit 4. A condenser shown connected in each of the main conductors of the link circuit 4 is for the purpose of separating the circuits by which battery is supplied to each one of the connected subscribers. Talking current is supplied from the battery 10 through the right and left-hand windings of the supervisory relay 57 to the instrument of the subscriber 2. In responseto this talking current, the contacts 59 of the relay 57 establish a shunt path from the battery 10 around the supervisory lamp 55, thereby extinguishing this lamp, in which position a resistance is connected in parallel with the winding of the relay 15.

In the manner described, a connection has been completed through the link circuit 4 to enable the subscribers 1 and 2 to carry on a conversation, at the conclusion of which it will now be assumed that each receiver has been returned to its respective switchhook. Cessation of talking current over the line 2 releases the supervisory relay 57, whereupon the separation of its contacts 59 disconnects the shunt path around the supervisory lamp 55, and the contacts 58 of this relay close a shunt path on the resistance unit 60, thereby permitting the lamp 55 to be again lighted by being connected in parallel with the winding of the relay 15. Cessation of talking current over the line 1 releases the supervisory relay 40, and separation of its contacts 43 disables the circuit through the ringing relay 62. This disabling of the relay 62 serves to guard a line, with which the calling plug 14 may be connected, against ringing current when the answering plug 11 is not connected with another subscribers line, or is connected with a line on which the receiver is not retained ofi itsswitch-hook. Separation of the contacts 41 of the relay 40 disconnects the shunt from around the supervisory lamp 44, and the contacts 42 of this relay establish a shunt path on the resistance 45, which operations result 7 in the lamp 44 being lighted.

A further action which takes place on the release of the supervisory relay 40 concerns the operation of the relay 35. In tracing the circuit of this relay through the battery 10, the contacts 26 of the relay 22, conductor 34, the winding of therelay 35, its contacts 37, thence to the upper side of the lamp 44, it will be noted that the winding of this relay is connected in parallel with the lamp 44, and accordingly this relay will be initially energized in unison with the first lighting of this lamp, provided the relay 22 is inert. On the operation of the relay 35, its contacts 36, which close circuit in advance of the separation of its contacts 37, substitute a connection to the upper side of the resistance unit 45 for the first connection to the upper side of the lamp 44, and the closing of the contacts 38 and the separa tion of the contacts 39 interpose a circuit interrupter 53 and a low resistance pilot relay 50 in series with the battery 10 to the contact 41 of the supervisory relay 40.

In order to describe the operation of a recall signal, let it be assumed that the connection between stations 1 and 2, as described, remains up under the display of the disconnect signals. And let it be further assumed that at this time the. receiver is removed from its switch-hook on the line 1 in making another call. The supervisory relay 40 responds and the separation of its contacts 42 removes the shunt path from the resistance unit 45. The closing of the contacts 41 of this relay connects the relay 50 and the interrupter 53 in parallel with the lamp 44. At each closure of the circuit through interrupter 53, the lamp 44 is extinguished, due to being shunted by the pilot relay 50, and the contacts 51 of this relay include a pilotlamp 52 on the battery 10 at each impulse of current through the relay 50. Therefore, in response to the alternate opening and closing of the interrupter 53, the supervisory lamp 44 and the pilot lamp 52 are correspondingly lighted and extinguished in opposite phase with respect to each other. This automatic flashing will continue so long as the receiver is retained ofi the switch-hook on the line 1. In response to this signal the operator removes the calling plug 14 from the jack 2. The relay 15 is thereby restored, and the closing of its contacts 16 completes the operating circuit of the listening relay 22, which will then be energized over the circuit already traced. The relay 22 disconnects the flashing control relay 35, operates the common relay 17, and includes the operators telephone set 33 with the link circuit 4, thereby setting the circuits in a position which has been described. The pilot relay 50, the pilot lamp 52 and the in terrupter 53 are common to a plurality of cord circuits.

In describing the operations which take place when one answering plug is connected with one subscribers line and another answering plug is connected with a second subscribers line, before the calling plug associated with the first answering plug has been connected to another subscribers line, let it be assumed that the plug 11 of thelink circuit 5 is inserted in the jack 3. The'listening relay 22 of this link circuit and the common relay 17 will be operated in a manner similar to that already de scribed for the first connection of the link circuit 4, the operators telephone set 33 being connected with the link circuit 5 through the conductors 28 and 29 and the associated contacts 23 and 24 of the common relay 22 individual to this link circuit. The insertion of the plug 11 of the link circuit 4 in the jack 12, in response to a call from the line 1, will now set up flashing of the supervisory lamp 44 and the pilot lamp 52 in the following manner: The listening relay 22 of this link circuit 4 remains inert due to its operating circuit being retained open at the associated contacts 18 of the common relay 17. The contacts 26 of the relay 22 permit the relay 35 to be operated in advance of the operation of the supervisory relay 40 as the signal circuit contacts of the plug 11 and the jack 12 make contact with each other in advance of the making of contact between the main or talking circuit contact members of this plug and jack. Flashing of the supervisory lamp 4 1 and the pilot lamp 52 will now take place in the same manner as already described for a recall operation, except that in the latter case the relay 22 remains inert due to the separation of the contacts 16 of the relay 15, while for the condition now being considered the relay 22 is disabled by the separation of its associated contacts 18 on the common relay 17. The flashing of the lamps 44: and 52 will continue so long as the receiver is retained off its switchhook by the subscriber 1, or until a connection is completed by means of the link circuit 5. To describe this operation it will be assumed that the calling plug 14 of the link circuit 5 is now inserted in the jack 2. The relay 15 associated with this link circuit is thereby operated in a manner similar to that described for operation of the corresponding relay on the link cir- I cuit 4, and the separation of its contacts 16 releases the relay 17, which disconnects the operators telephone set 33 from this link circuit and releases the common relay 17 all through the action of contacts corresponding to and including the operations described for the relay 22 of the link cir-' cuit 1. On the instant the contacts 18 of the common relay 17 engage, on the release of this relay, circuit will be completed through the listening relay 17 of the link circuit 4;, and the operators telephone set 33 will be included with this link circuit; the flashing-control relay 35 will be disconnected and the common relay 17 will be operated in the same manner as described for the first connection with this-link circuit.

It will be understood that the several batteries 10, as shown in the drawing, may be and preferably are one and the samebat tery.

VVhat' is claimed is:

1. A telephone exchange System comprising telephone lines, link circuits for interconnecting the lines, an operators telephone set, an electromagnetic switching device for each link circuit operating upon connection thereof with a' telephone line to connect therewith the operators telephone set, and a common electromagnetic switching mechanism actuated upon the operation of one switching device to disable all other switching devices.

8. A telephone exchange system comprising telephone lines, link circuits for interconnecting the lines, an operators telephone set, a listening relay for each link circuit operating upon connection thereof with a telephone line to connect therewith the op-' erators telephone set, and a common relay actuated upon the operation of one listening relay to disable all other listening relays.

at. A telephone exchange system comprisingtelephone lines, link circuits for interconnecting the lines, an operators telephone set, a switching device for each link circuit operating upon connection thereof with a line, to connect the operators telephone set therewith, a common switching mechanism operating upon the actuation of one switching device to disable all other switching devices, and switching means operating upon connection of the link circuit in use with another line to restore the switching device thereof and the common switching mechanism to normal position. 1

5. In a telephone exchange system, a plurality of subscribers lines, a plurality of link circuits for interconnecting said subscribers lines, supervisory signals for said link circuits, an operators telephone set, switching means for automatically including said operators telephone set with. said link circuits, common switching means for automatically preventing the inclusion of said operators telephone set with more than one of said link circuits at the same time, and switching means for automatically rendering a characteristic operation of the supervisory signal of a second link circuit connected for answering another subscribers line during the time the operators telephone set is included with another-one of said link circuits.

6. A telephone exchangesystem comprising telephone lines, link circuits for interconnecting the lines, a pilot signal common to the link circuits, an operators telephone set, a switching device for each link circuit operating upon connection thereof with a line to connect the operators telephone set therewith, a common switching mechanism operating upon the actuation of one switching device to disable all other switching devices, and electromagnetic mechanism'operating upon connection of a second link circuit with another line while one switching device is operated to cause the operation of the pilot'signal. I

7. In a telephone exchange system, a plurality of subscribers lines, a plurality of link circuits for interconnecting said subscribers 'lines, supervisory signals for said link circuits, a pilot signal common to said plurality of link circuits, a circuit interrupting means, an operators telephone set, switching means for automatically including said operators set with said link circuits, a common switching means for automatically permitting said operators telephone set to be included with a first link circuit connected for answering one of said subscribers lines and to prevent the inclusion of said operators telephone set with a second link circuit subsequently connected to answer another one of said subscribers lines, and switching means for rendering said circuit interrupting means effective to cause automatic intermittent operation of said pilot signal and supervisory signal of the said second connected link circuit.

8. In a telephone switching system, a plurality of subscribers lines, a plurality of link circuits for interconnecting said subscribers lines, a pilot signal common to said plurality of link circuits, supervisory sig nals for said link circuits, an operators telephone set, a circuit interrupting means, switching means for automatically including said operators set with said link circuits, a common switching means forautomatically preventing the inclusion of said operators set with more than one of said link circuits at the same time, means for rendering a disconnect indication on said supervisory signals, and a switching means for rendering flashing indications on said pilot signal and a supervisory signal of a link circuit when a subscriber initiates a call during the time a disconnect signal is displayed on the supervisory signal of the link circuit which is connected with the said subscribers line.

9. In a telephone exchange system; a plurality of subscribers lines; a plurality of link circuits for interconnecting said lines; an operators telephone set; first relays for each of said link circuits for including said operators telephone set therewith when the answering end of a link circuit is connected with one of said subscribers lines; a second relay for disconnecting said operators telephone set from said link circuit when the calling end of the link circuit is connected with another subscribers line; and a relay common to a plurality of said link circuits for preventing the operation of more than one of said first relays at the same time.

10. In a telephone exchange system; a plurality of subscribers lines; a plurality of link circuits for interconnecting said lines; an operators telephone set; first relays for each of said link circuits rendered operative by the inclusion of the answering end of the link circuit with a subscribers line, for including said operators telephone set therewith; a relay common to a plurality of said link circuits, operated by said first relay, to prevent the inclusion of said operators telephone set with a second link circuit, the answering end of which is connectedto another subscribers line; a second relay for each of said link circuits, operated by the inclusion of the calling end of a link circuit with a subscribers line, to disable said first relay to exclude said operators telephone set from said link circuit; and circuit controlling contacts associated with said first relay to render said common relay effective to permit the operation of the first relay of said second connected link circuit to include the said operators telephone set therewith.

11. In a telephone exchange system; a plurality of subscribers lines; a plurality of link circuits for interconnecting said lines; signals for said link circuits; an operators telephone set; a circuit interrupter means; a first relay for each of said link circuits for including said operators set therewith; a relay common to a plurality of said link circuits for preventing the inclusion of said operators telephone set with more than one of said link circuits at the same time; a second relay for each one of said link circuits for controlling the operation of said circuit interrupter means; and circuit controlling contacts operated by said first relay to operate said second relay to render said circuit interrupter means efiective to fiash the signal of the answering end of a second link circuit, which may be connected with a subscribers line during the time the answering end only of another link circuit is connected with another subscribers line.

12. In a telephone exchange system; a plurality of subscribers lines; a plurality of link circuits for interconnecting said lines;

signals for said link circuits; an operators telephone set; a first relay for each of said link circuits for including said operators telephone set therewith; a second relay for each of said link circuits for excluding said operators set therefrom; a relay common to a plurality of said link circuits for preventing the inclusion of said operators telephone set with more than one of said link circuits at the same time; a circuit interrupter means; a third relay for each of said link circuits to control the operation of said circuit interrupter means; a supervisory relay for each of said link circuits; and circuit controlling contacts operated by said supervisory relay for rendering said third relay operative to cause said circuit interrupter means effective to flash said signal.

13. A telephone exchange system comprising telephone lines, link circuits for interconnecting the lines, an operators telephone set, a listening relay for each link circuit operating upon connection thereof with a telephone line to connect the operators telethe listening relay thereof and the connectphone set therewith, a common relay actuing relay.

ated upon the operation of one listening In Witness whereof, I hereunto subscribe 10 relay to disable all other listening relays, my name this fifth (lay of November A. D.,

g; and electromagnetic mechanism operating 1915.

upon connection of the link circuit in use p With another telephone line to release both HENRY P. CLAUSEN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

